TypeError: Cannot read property 'buildError' of undefined

[yiye]

Bug Report

Current Behavior
A clear and concise description of the behavior.

Input Code

• REPL or Repo link if applicable:

TypeError: Cannot read property 'buildError' of undefined
    at Scope.checkBlockScopedCollisions (/Users/puss/work/ioc/parrot-tool-must/node_modules/_@babel_traverse@7.0.0@@babel/traverse/lib/scope/index.js:347:22)
    at Scope.registerBinding (/Users/puss/work/ioc/parrot-tool-must/node_modules/_@babel_traverse@7.0.0@@babel/traverse/lib/scope/index.js:504:16)
    at Scope.registerDeclaration (/Users/puss/work/ioc/parrot-tool-must/node_modules/_@babel_traverse@7.0.0@@babel/traverse/lib/scope/index.js:452:14)
    at Object.Declaration (/Users/puss/work/ioc/parrot-tool-must/node_modules/_@babel_traverse@7.0.0@@babel/traverse/lib/scope/index.js:125:12)
    at NodePath._call (/Users/puss/work/ioc/parrot-tool-must/node_modules/_@babel_traverse@7.0.0@@babel/traverse/lib/path/context.js:53:20)
    at NodePath.call (/Users/puss/work/ioc/parrot-tool-must/node_modules/_@babel_traverse@7.0.0@@babel/traverse/lib/path/context.js:40:17)
    at NodePath.visit (/Users/puss/work/ioc/parrot-tool-must/node_modules/_@babel_traverse@7.0.0@@babel/traverse/lib/path/context.js:88:12)
    at TraversalContext.visitQueue (/Users/puss/work/ioc/parrot-tool-must/node_modules/_@babel_traverse@7.0.0@@babel/traverse/lib/context.js:118:16)
    at TraversalContext.visitMultiple (/Users/puss/work/ioc/parrot-tool-must/node_modules/_@babel_traverse@7.0.0@@babel/traverse/lib/context.js:85:17)
    at TraversalContext.visit (/Users/puss/work/ioc/parrot-tool-must/node_modules/_@babel_traverse@7.0.0@@babel/traverse/lib/context.js:144:19)

Environment

• Babel version(s): [v7.0.0]
• Node/npm version: [Node v10.9.0/npm 5.15.0]
• OS: [e.g. OSX 10.13.6]
• Monorepo [e.g. yes/no/Lerna]
• How you are using Babel: [AST parser]
  .

[babel-bot]

Hey @yiye! We really appreciate you taking the time to report an issue. The collaborators
on this project attempt to help as many people as possible, but we're a limited number of volunteers,
so it's possible this won't be addressed swiftly.

If you need any help, or just have general Babel or JavaScript questions, we have a vibrant Slack
community that typically always has someone willing to help. You can sign-up here
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[loganfsmyth]

This may be a duplicate, but it's hard to tell without a full reproduction example. What config and input source are you using to produce this error? How are you calling Babel? It would be great if you could provide a repository that reproduces the error.

[chrisregnier]

I'm getting the same thing where hub isn't defined.
Here's the rough outline of what I'm doing.

let code = `
  function foo(v) {
    let v = 8
  }
`;
let ast = parse(code, {
  sourceType: 'module',
  sourceFilename: 'failingTest',
  ranges: true,
  plugins: [
    'jsx',
    'flow',
    'classProperties',
    'objectRestSpread'
  ]
})
traverse(ast, {
  Program(path) {
    console.log('here')
  }
}, null, { stateData: {} });

[chrisregnier]

ya this looks like a duplicate of #8262 , although I don't t think it needs to be typescript.

[loganfsmyth]

Cool, this is actually a duplicate of #8617. That other one is triggering the same broken code, but that other one isn't supposed to trigger an error in the first place.

[loganfsmyth]

And to clarify, #8617 is what is causing your code snippet to throw an unhelpful error message, but your example code is a valid error, just to clarify, in case you wanted it to not throw.

[chrisregnier]

ya I believe they all have the same cause. Looks like hub isn't initialized in our case in the root path so when context.create tries to grab it recursively from the parentPath, nothing's there. I've gotten the error here and the one in 8262 for the same reason, but with slightly different test code.

[loganfsmyth]

Yup, I mostly clarify because for #8262 it is different because it actually shouldn't be a "Duplicate declaration" in the first place.